There has been a continuing need in the industry for aminopolysiloxanes which are useful for treating textiles and fabrics without discoloration or yellowing of such textiles and fabrics, and for aminoalkyl-endblocked siloxanes which are useful in the preparation of siloxane-containing block copolymers with surface-active properties. There has also been a continuing need for simpler processes for making said aminosiloxanes and aminoalkyl-endblocked siloxanes, particularly regarding the starting materials from which they are prepared.
The preparation of aminoalkylsilanes containing hindered 4-amino-3,3-dialkylbutyl groups is described in U.S. Pat. No. 5,354,880, which is incorporated herein by reference. The conversion of said aminoalkylsilanes to aminosiloxanes with 4-amino-3,3-dialkylbutyl groups is described in copending U.S. application Ser. No. 08/834,633, which is incorporated herein by reference. Prior methods for the preparation of siloxanes with 4-amino-3,3-dialkylbutyl groups have involved the preparation of dialkoxy 4-amino-3,3-dialkylbutylsilanes and their hydrolyses to aminosiloxane intermediates which were equilibrated with hexamethyldisiloxane, octamethylcyclotetrasiloxane, or other reactants to form the final aminosiloxanes with 4-amino-3,3-dialkylbutyl groups and a majority of dimethylsiloxane units. The dialkoxy 4-amino-3,3-dimethylbutylsilanes were prepared by a sequence of reactions beginning with the base-catalyzed addition of isobutyronitrile to a vinyl alkoxy silane, and subsequent hydrogenation of the nitrile adduct to the corresponding aminoalkylsilane. ##STR1##